If you are riding a bike in foreign countries, you need to know what these traffic signs mean.

1		This sign means “walk”, you can cross the street along with other people.
2		This sign is the “don't walk” sign. It means you should stop to wait for a while until the sign of “walk” is showing.
3		This sign means that there is a bike lane. If you see such a sign, you must use the bike lane.
4		Car drivers and bike riders must come to a complete stop at “STOP” signs.
5		This sign means you are coming to a zebra crossing. You must slow down to allow people in the zebra crossing to cross the street.
6		This sign means parts of the road are rough. Be careful! Rough roads make you fall off your bike.

    Why is music so important to children? Here are some of my thoughts on the subject.

    Music has a positive（积极的） effect on young children's development!

    New research shows that music has a good influence on young children's cognitive（认知的） skills, such as spatial reasoning（空间推理） and memory. Research also shows that offering children an interesting environment can support children's healthy growth and development.

    Young children enjoy making music with others!

    Making music with others gives children a wonderful feeling of belonging to the group. Children might have difficulty joining in activities with others because they are shy, have limited language ability or special needs, but they can freely take part in a music activity.

    Music makes young children happy!

    Children seem to experience much pleasure and joy when listening to music, making music and dancing to music. Whether they are singing along to a CD, playing an instrument or dancing to music around the classroom, most children seem to thoroughly（彻底地） enjoy participating in a music activity. How wonderful it is to offer children the chance to do some activities about music!

    Butterflies are common all over the world, but butterflies in hotter countries are usually bigger and more brightly colored than those in cooler countries, and they are more different kinds.

    Usually the male(雄性的)butterflies are more brightly colored than the females. The females have bigger and heavier bodies since they carry the eggs. The bright colors of the males help to attract the females, and the duller(较暗淡的)colors of the females make them less likely(可能的)to be caught by enemies before they have laid their eggs.

    Some butterflies hare bright pattern colors on the upper surface of their wings that show when flying, but when they rest on a tree or leaves, they close their wings. On the undersides of their wings there are green and brown marks which look like the tree or leaves. They are then difficult to be seen. The best example of this is the Dead Leaf Butterfly. When its wings are closed, it looks exactly like a dead leaf. There are even marks that look like the holes in a dead leaf. When the butterfly is run after by a bird, it closes its wings and seems to have disappeared completely.

    Many butterflies have round marks on their wings that look like eyes. The round marks have a useful function(功能). When the butterflies are resting, their wings are closed, and these marks can't be seen. When a bird sees one, and begins to attack it, the butterfly will open its wings. The bird thinks that it sees two eyes staring at it, frightened, and flies away.

    SoFi is a special "fish". It is 47 centimeters long. It is all white. It has a small round head. What kind of fish is it? Actually, SoFi is a soft robotic fish. Scientists from MIT made it look like a real fish. They want to use it to study sea animals when the ocean environment changes.

    SoFi's skin is made of a kind of rubber. It's soft. The robotic fish's head is 3D printed. There is a camera in its nose and it can take photos and videos underwater. SoFi can swim among real fish. It is quiet. It doesn't scare other fish. It can also turn left and right, and even change its speed.

    Although SoFi is not the first lifelike robotic fish, it is the most advanced of its kind, according to MIT scientists. Many other countries have also made robotic fish, including the UK and China. Scientists said these robotic fish can easily get close to other fish. And other fish can even interact (互动) with them.